1. Field of the Invention
The present invention relates to a serial bus data control device used for a serial bus such as a well-known IEEE 1394 serial bus (hereinafter referred to as an “IEEE 1394 bus”) which is mounted, for example, on computers and/or peripheral equipment adapted to control sending and receiving of data transferred through the serial bus between the computer and peripheral equipment and more particularly to the serial bus data control device capable of performing more efficient processing of received data.
2. Description of the Related Art
When a series of data representing a certain kind of information is transferred through the IEEE 1394 bus between a computer and a peripheral equipment, each being equipped with a serial bus data control device for the bus, a plurality of packets containing divided data each having an individually predetermined length of data is received and sent between the computer and the peripheral equipment. Each of the packets is composed of a header constituting a head portion of each packet, actual data i.e., divided data having an individually predetermined length and a footer constituting a tail portion of the packet. Conventionally, when a packet as described above is sequentially transferred through the IEEE 1394 bus from a sending device, i.e., a sending node to a receiving device. i.e., a receiving node, the data contained in each of the packets is stored temporarily in a buffer mounted in a serial bus data control device of the receiving node. As shown in FIG. 6, in a buffer of a conventional serial bus data control device, after a header, actual data and a footer contained in a packet 1 received first are stored in the buffer in order of addressed memory locations, a subsequently received packet 2 is stored after the footer of the packet 1. Then, a subsequently received packet 3 is sequentially stored after the footer of the packet 2. The receiving node, to reconstruct a series of original data from two or more received packets, then extracts only actual data from each of the packets stored in the buffer by selecting an address assigned to the actual data and by reading the actual data having the selected address from the buffer in order.
However, as described above, in the receiving node having such a conventional serial bus data control device, to reconstruct original data from two or more received packets, it is necessary to select and read only actual data positioned between a header and a footer, that is, divided by the header and the footer, out of the header, actual data and footer contained in each of the packets stored in the buffer. Therefore, processing of data contained in each of the received packets on the receiver node side becomes very complicated, thus making it difficult to achieve a prompt and speedy reconstruction of data.